/*
自己选择的路 ,跪着也要走完。朋友们 , 虽然这个世界日益浮躁起来,只
要能够为了当时纯粹的梦想和感动坚持努力下去 , 不管其它人怎么样,我
们也能够保持自己的本色走下去。
To the world , you will be a person , but to a person , you
will be the world .                               ——AKPower
*/
#include <iostream>
#include <cmath>
#include <algorithm>
#include <cstring>
#include <vector>
#include <map>
#include <queue>
#include <cstdio>
#include <string>
#include <stack>
#include <set>
#define IOS ios::sync_with_stdio(false), cin.tie(0)
using namespace std;
typedef unsigned long long ll;
bool flag[100];

int main()
{
    IOS;
    ll a, b, x, y;
    // ll ans;
    cin >> a >> b;
    if (a < b)
    {
        cout << -1 << endl;
        return 0;
    }
    x = a - b;
    x >>= 1;
    if ((a % 2 == 0 && b % 2 == 1) || (a % 2 == 1 && b % 2 == 0))
        cout << -1 << endl;
    else
        cout << x << " " << a - x << endl;
    getchar();
    getchar();
    return 0;
}
